[GordonS]

I'm truly surprised you've seen Windows containers in the wild - across dozens of engagements with very firm Microsoft shops, I've never seen them, nor seen the need. Gods, even MSSQL runs on Linux these days!

I'm also very surprised you'd claim that not all Microsoft shops are buying into dotnet core - I've seen the very opposite; every client I've worked with has known dotnet framework has been superceded by core, and has been eager to move. A decent portion of this is driven by certain containerisation, which (realistically) means dotnet on Linux.

The only real limitation with dotnet core has been the lack of managed C++ support - a niche use case, and only relevant on Windows, but even this has been resolved in dotnet core 3.1.

Considering the not insubstantial performance improvements in dotnet core, and of course the benefit of cross-platform code, I'm really interested to hear about the limitations of dotnet core you've found (the switch for me and all the enterprise clients I've worked with has been great)?

[pjmlp]

Plenty of Microsoft shops are deeply invested in technologies like WCF, EF6, ODP.NET, WPF/Forms component libraries, commercial CMS stacks (e.g. Sitecore), and aren't willing to allocate budgets to rewrite what is working perfectly fine.

The kind of enterprises where deployments on IIS, with AD infrastructure on premises, Windows on all company layers are still the name of the game, with some Linux servers for running SAP and a couple of other Java based services.

What is missing from .NET Core 3.1?

Besides what I have listed above, EF 6 on Core doesn't support the Visual Studio graphical tooling nor the EF 6 .NET Framework EF providers, WPF/Forms designers are still WIP and have issues with commercial component libraries, WCF well, no one is looking forward to rewrite their working code with gRPC.

And many are still a little burned with Silverlight and how the whole WinRT, UAP, UWP story went.

Back in the .NET Code 2.0 days, I had a project to rewrite a .NET Application into Java, because the customer in question saw a better business value in doing so than investing in .NET Core. Mainly because .NET Core didn't had support for some critical libraries being used in the .NET Application, while the libraries vendor did support a Java counterpart for them.

Yes, they will eventually move to .NET Core, when it makes business sense to allocate budget to do so.

That is just my experience, others will vary.